M x=(6m+1)/6 ...,-11/6 ,-5/6 ,1/6,7/6,13/6,19/6,...
N x=(3n-2)/6 ...,-8/6 ,-5/6 ,-2/6,1/6,4/6,7/6,...
P x= (3p+1)/6 ...,-8/6 ,-5/6 ,-2/6,1/6,4/6,7/6,...
N=P,且M是它的真子集.
M x=(6m+1)/6 ...,-11/6 ,-5/6 ,1/6,7/6,13/6,19/6,...
N x=(3n-2)/6 ...,-8/6 ,-5/6 ,-2/6,1/6,4/6,7/6,...
P x= (3p+1)/6 ...,-8/6 ,-5/6 ,-2/6,1/6,4/6,7/6,...
N=P,且M是它的真子集.